1. Field of Invention
The present invention relates to a method for producing a solution of sodium ammonium phosphate having a reduced carbon dioxide content by the reaction of monoammonium phosphate and sodium carbonate at elevated temperature in a vertical column having vapor-liquid contact means whereby carbon dioxide is removed from the reaction mixture while substantially all ammonia is retained in the product.
The solution thus formed may be utilized as a source for crystalline sodium ammonium phosphate or as an intermediate in the preparation of various sodium phosphates, pyrophosphates and polyphosphates for example in the process disclosed in U.S. Pat. Appln. Ser. No. 537,234 filed simultaneously herewith in which the sodium ammonium phosphate is decomposed to produce ammonia and a substantially ammonia-free solution of alkali metal orthophosphate.